A Forum for discussion of water gardening including ponds, bogs, bowls, fountains and waterfalls. The scope ranges from design and construction, associated plants, fish and wildlife, maintenance and simple enjoyment.

We have 2 spring-fed natural ponds simply dug out of the heavy clay! They are not terribly deep - about 12 - 18 inches - but have loads of reeds, rushes, water lilies, nardoo and other wate plants surrounding and in the water. Both have 9 VERY healthy, large goldfish and 100's of tadpoles in them but are also subjected to a lot of leaves, bark, twigs, bird and possum poo falling into them.

They are about 2 years old and in the last 6-8 months first the smaller more sunny pond developed blanket weed and now the bigger and shadier pond has it too. I scoop it out and it returns with a vengeance. Now we have tried the Interpet Blanket Weed Buster and it has had minimal effect, probably because the springs keep filling the ponds up! Despite blocking off the overflow pipes, a bit of water still manages to seep out or the ponds overflow into the surrounding garden washing in MORE nutrients!

Anyone have any similar experiences or any suggestions. Barley straw? Can we dose it again and again with the BW buster, say, on a weekly basis?

Thanks cordelia - have looked at all these options already! This one in the link is no good for our ponds as the nutrient levels in the ponds are too high (iron rich clay doesn't help!) and the price bit too much!

Will keep loking - tricky when the ponds are natural and no pumps or filters! Now that we've had rain, maybe they'll get a good flush!

4 large goldfish produce a fair bit of wee and poo, which adds to the nutrient soup. how many litres of water in the pond? do you have any filter installed?

if you're fairly certain that the clay is overloading the water with nutrients...get pond lining. on second thought....take a sample of the water down to an aquarium shop (in a closed vial), and they'll happily test it for you in the hope of some sale. Don't buy anything, just find out which elements exactly are in over-supply. I'm fairly certain that this type of algae thrives in nitrogen rich water.

for the debris falling in...install a sturdy canvas fairly high over the pond. high enough so it's not in the field of view. second hand army tent canvas would be great strung up between trees, with a slight fall so the rain runs off below the pond(s).